1. Field of the Invention
The present invention relates to a digital watermark embedding apparatus for embedding particular embedding information with little adverse effect on image quality or sound quality of multimedia data such as an image, a moving image, and a sound, a digital watermark detecting apparatus for detecting the embedded particular embedding information, and a digital watermark system obtained by integrating the digital watermark embedding apparatus and the digital watermark detecting apparatus.
2. Description of the Related Art
Conventional digital watermarking of an open algorithm type enables information regarding digital watermark extraction to be made open by applying error-correction coding not only to information to be embedded but also to an entire image or an entire data group available for embedding (for example, see Yamaguchi, Iwamura, Imai, “Digital Watermark of Open Algorithm Type using Error-Correction Coding”, Proceedings of the 1999 Symposium on Cryptography and Information Security, pp. 713-728, 1999).
However, the conventional technologies have the following problems. The conventional digital watermarking of an open algorithm type has required, due to the application of error-correction coding, parity bits to be embedded so as to be accurately detected in addition to information that is primarily desired to be embedded as a digital watermark. This has caused problems that embedding space for the information that is primarily desired to be embedded as the digital watermark is reduced and that degradation of image quality occurs due to embedding of the parity bits.